This section is intended to provide a background or context to the embodiments that are recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.
High Speed Packet Access (HSPA) is a protocol used within Universal Mobile Telecommunication System (UMTS) and it comprises two mobile telephony protocols: High Speed Downlink Packet Access (HSDPA) and High Speed Uplink Packet Access (HSUPA). HSPDA and HSUPA extend and improve the performance of existing UMTS protocols by improving the capacity and throughput while reducing latency. In particular, HSUPA provides fast uplink packet switch data services with a shorter Transmission Time Interval (TTI) and Hybrid ARQ (HARQ) with incremental redundancy, which makes retransmissions more effective. In HSUPA, the Enhanced Dedicated Physical Data Channel (E-DPDCH) and the Enhanced Dedicated Physical Control Channel (E-DPCCH) are provided to carry the uplink packet data and the associated control information, respectively.
HSUPA also uses a packet scheduler that operates on a request-grant basis, where at any given time, a number of User Equipments (UEs) may request a permission to send data in the uplink direction. In requesting data transmissions, the UEs typically send information such as scheduling information messages that include information such as queue lengths, power headroom and the like. In response, the HSUPA scheduler allocates radio resources on the uplink to the requesting UEs. The amount of data that a UE can transmit depends on the transmit power grant allocated to that UE by the HSUPA scheduler. The higher the grant, the more data a UE can transmit. In order to ensure fidelity of uplink transmissions, it is important to keep the total interference or total received power, measured commonly as rise over thermal (RoT) noise floor, under tight control and equivalently to ensure RoT stability. While the HSUPA scheduler in a cell can exert control over the scheduling and power allocation for the HSUPA UEs that are served by this cell, the scheduler cannot control the transmissions of non-HSUPA UEs. For example, the HSUPA scheduler cannot control UEs that operate pursuant to UMTS Release 99 (R99) or the Release 5 (Rel 5) standard that are connected to the current cell. In fact, such UMTS R99/Rel-5 systems do not operate on a request-grant basis. Furthermore, the HSUPA scheduler cannot control other interfering UEs that are served by other cells.